Multi-speed transmission

ABSTRACT

A transmission has an input member, an output member, at least four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes actuatable in combinations of three to establish a plurality of forward gear ratios and at least one reverse gear ratio.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices and more particularly to a transmission having tenor more speeds, at least four planetary gear sets and a plurality oftorque transmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches, planetary gear arrangements and fixed interconnections toachieve a plurality of gear ratios. The number and physical arrangementof the planetary gear sets, generally, are dictated by packaging, costand desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

In an embodiment of the present invention, the first, second, third andfourth planetary gear sets each having a sun gear, a carrier member anda ring gear.

In still another embodiment of the present invention, the input memberis continuously connected for common rotation with the carrier member ofthe second planetary gear set.

In still another embodiment of the present invention, the output memberis continuously connected for common rotation with the carrier member ofthe fourth planetary gear set.

In still another embodiment of the present invention, a firstinterconnecting member continuously interconnects the carrier member ofthe first planetary gear set with the carrier member of the thirdplanetary gear set and the ring gear of the fourth planetary gear set.

In still another embodiment of the present invention, a secondinterconnecting member continuously interconnects the sun gear of thefirst planetary gear set with the sun gear of the second planetary gearset.

In still another embodiment of the present invention, a thirdinterconnecting member continuously interconnects the ring gear of thesecond planetary gear set with the sun gear of the third planetary gearset.

In yet another embodiment of the present invention, a first torquetransmitting mechanism is selectively engageable to interconnect thecarrier member of the second planetary gear set and the input memberwith the sun gear of the fourth planetary gear set.

In yet another embodiment of the present invention, a second torquetransmitting mechanism is selectively engageable to interconnect the sungear of the third planetary gear set with the sun gear of the fourthplanetary gear set.

In yet another embodiment of the present invention, a third torquetransmitting mechanism is selectively engageable to interconnect thering gear of the third planetary gear set with the sun gear of thefourth planetary gear set.

In yet another embodiment of the present invention, a fourth torquetransmitting mechanism is selectively engageable to interconnect thering gear of the third planetary gear set with the carrier member of thefourth planetary gear set.

In yet another embodiment of the present invention, a fifth torquetransmitting mechanism is selectively engageable to interconnect thering gear of the first planetary gear set with the stationary member.

In yet another embodiment of the present invention, a sixth torquetransmitting mechanism is selectively engageable to interconnect the sungear of the first planetary gear set with the stationary member.

In yet another embodiment of the present invention, the torquetransmitting mechanisms are selectively engageable in combinations of atleast three to establish a plurality of forward speed ratios and atleast one reverse speed ratio between the input member and the outputmember.

Further features, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic illustration of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmissions illustrated inFIGS. 1, 2 and 3.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that the embodiments of themulti-speed automatic transmissions of the present invention have anarrangement of permanent mechanical connections between the elements ofthe four planetary gear sets. For example, a second component or elementof a first planetary gear set is permanently coupled to a secondcomponent or element of the third planetary gear set and a firstcomponent or element of the fourth planetary gear set. A third componentor element of the first planetary gear set is permanently coupled afirst component or element of the second planetary gear set. A thirdcomponent or element of the second planetary gear set is permanentlycoupled to a third component or element of the third planetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear are each represented by a node. Therefore, a single lever containsthree nodes: one for the sun gear, one for the planet gear carrier, andone for the ring gear. The relative length between the nodes of eachlever can be used to represent the ring-to-sun ratio of each respectivegear set. These lever ratios, in turn, are used to vary the gear ratiosof the transmission in order to achieve an appropriate ratios and ratioprogression. Mechanical couplings or interconnections between the nodesof the various planetary gear sets are illustrated by thin, horizontallines and torque transmitting devices such as clutches and brakes arepresented as interleaved fingers. Further explanation of the format,purpose and use of lever diagrams can be found in SAE Paper 810102, “TheLever Analogy: A New Tool in Transmission Analysis” by Benford andLeising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14, a second planetary gear set 16, a third planetarygear set 18 and a fourth planetary gear set 20 and an output shaft ormember 22. In the lever diagram of FIG. 1, the first planetary gear set14 has three nodes: a first node 14A, a second node 14B and a third node14C. The second planetary gear set 16 has three nodes: a first node 16A,a second node 16B and a third node 16C. The third planetary gear set 18has three nodes: a first node 18A, a second node 18B and a third node18C. The fourth planetary gear set 20 has three nodes: a first node 20A,a second node 20B and a third node 20C.

The input member 12 is continuously coupled to the second node 16B ofthe second planetary gear set 16. The output member 22 is coupled to thesecond node 20B of the fourth planetary gear set 20. The second node 14Bof the first planetary gear set 14 is coupled to the second node 18B ofthe third planetary gear set 18 and the first node 20A of the fourthplanetary gear set 20. The third node 14C of the first planetary gearset 14 is coupled to the first node 16A of the second planetary gear set16. The third node 16C of the second planetary gear set 16 is coupled tothe third node 18C of the third planetary gear set 18.

A first clutch 24 selectively connects the input member or shaft 12 andthe second node 16B of the second planetary gear set 16 with the thirdnode 20C of the fourth planetary gear set 20. A second clutch 26selectively connects the third node 16C of the second planetary gear set16 and the third node 18C of the third planetary gear set 18 with thethird node 20C of the fourth planetary gear set 20. A third clutch 28selectively connects the first node 18A of the third planetary gear set18 with the third node 20C of the fourth planetary gear set 20. A fourthclutch 30 selectively connects the first node 18A of the third planetarygear set 18 with the second node 20B of the fourth planetary gear set 20and the output member 22. A first brake 32 selectively connects thefirst node 14A of the first planetary gear set 14 with a stationarymember or transmission housing 50. A second brake 34 selectivelyconnects the first node 16A of the second planetary gear set 16 and thethird node 14C of the first planetary gear set 14 with the stationarymember or transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofan embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14C, aring gear member 14A and a planet gear carrier member 14B that rotatablysupports a set of planet gears 14D (only one of which is shown). The sungear member 14C is connected for common rotation with a first shaft orinterconnecting member 42 and a second shaft or interconnecting member44. The ring gear member 14A is connected for common rotation with athird shaft or interconnecting member 46. The planet carrier member 14Bis connected for common rotation with a fourth shaft or interconnectingmember 48. The planet gears 14D are each configured to intermesh withboth the sun gear member 14C and the ring gear member 14A.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The sun gearmember 16A is connected for common rotation with the second shaft orinterconnecting member 44. The ring gear member 16C is connected forcommon rotation with a fifth shaft or interconnecting member 52. Theplanet carrier member 16B is connected for common rotation with theinput shaft or member 12. The planet gears 16D are each configured tointermesh with both the sun gear member 16A and the ring gear member16C.

The planetary gear set 18 includes a sun gear member 18C, a ring gearmember 18A and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The sun gearmember 18C is connected for common rotation with the fifth shaft orinterconnecting member 52 and a sixth shaft or interconnecting member54. The ring gear member 18A is connected for common rotation with aseventh shaft or interconnecting member 56. The planet carrier member18B is connected for common rotation with the fourth shaft orinterconnecting member 48. The planet gears 18D are each configured tointermesh with both the sun gear member 18C and the ring gear member18A.

The planetary gear set 20 includes a sun gear member 20C, a ring gearmember 20A and a planet gear carrier member 20B that rotatably supportsa set of planet gears 20D (only one of which is shown). The sun gearmember 20C is connected for common rotation with an eighth shaft orinterconnecting member 58. The ring gear member 20A is connected forcommon rotation with the fourth shaft or interconnecting member 48. Theplanet carrier member 20B is connected for common rotation with a ninthshaft or interconnecting member 60 and with the output shaft or member22. The planet gears 20D are each configured to intermesh with both thesun gear member 20C and the ring gear member 20A.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or clutches 24, 26, 28, 30 and brakes32 and 34 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 24 is selectively engageable toconnect the input shaft or member 12 with the eighth shaft orinterconnecting member 58. The second clutch 26 is selectivelyengageable to connect the sixth shaft or interconnecting member 54 withthe eighth shaft or interconnecting member 58. The third clutch 28 isselectively engageable to connect the seventh shaft or interconnectingmember 56 with the eighth shaft or interconnecting member 58. The fourthclutch 30 is selectively engageable to connect the seventh shaft orinterconnecting member 56 with the ninth shaft or interconnecting member60. The first brake 32 is selectively engageable to connect the thirdshaft or interconnecting member 46 with the stationary element or thetransmission housing 50 in order to restrict the member 46 from rotatingrelative to the transmission housing 50. The second brake 34 isselectively engageable to connect the first shaft or interconnectingmember 42 with the stationary element or the transmission housing 50 inorder to restrict the member 42 from rotating relative to thetransmission housing 50.

Referring now to FIG. 2 and FIG. 3, the operation of the ten speedtransmission 10 will be described. It will be appreciated thattransmission 10 is capable of transmitting torque from the input shaftor member 12 to the output shaft or member 22 in at least ten forwardspeed or torque ratios and at least one reverse speed or torque ratio.Each forward and reverse speed or torque ratio is attained by engagementof one or more of the torque-transmitting mechanisms (i.e. first clutch24, second clutch 26, third clutch 28, fourth clutch 30, first brake 32and second brake 34), as will be explained below. FIG. 3 is a truthtable presenting the various combinations of torque-transmittingmechanisms that are activated or engaged to achieve the various gearstates. An “X” in the box means that the particular clutch or brake isengaged to achieve the desired gear state. Actual numerical gear ratiosof the various gear states are also presented although it should beappreciated that these numerical values are exemplary only and that theymay be adjusted over significant ranges to accommodate variousapplications and operational criteria of the transmission 10. Of course,other gear ratios are achievable depending on the gear diameter, gearteeth count and gear configuration selected.

For example to establish first a reverse gear (REV1), fourth clutch 30and first and second brakes 32 and 34 are engaged or activated. Thefourth clutch 30 connects the seventh shaft or interconnecting member 56with the ninth shaft or interconnecting member 60. The first brake 32connects the third shaft or interconnecting member 46 with thestationary element or the transmission housing 50 in order to restrictthe member 46 from rotating relative to the transmission housing 50. Thesecond brake 34 connects the first shaft or interconnecting member 42with the stationary element or the transmission housing 50 in order torestrict the member 42 from rotating relative to the transmissionhousing 50. Likewise, the ten forward ratios are achieved throughdifferent combinations of clutch and brake engagement, as shown in FIG.3. Moreover, the transmission 10 of the present invention is capable ofproducing alternate gear ratios for a given gear state, as shown in FIG.3. For example, a second reverse gear ratio (REV2) is achieved throughthe engagement of second clutch 28 and first and second brakes 32 and34. Additionally, alternate gear ratios are also provided in FIG. 3 forgear states 4, 7 and 10. The alternate gear ratios are achieved, asindicated in a FIG. 3, through the selective engagement of torquetransmitting members 24, 26, 28, 30, 32 and 34.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches not specifically referenced in a given gear state areinactive or disengaged and, second of all, that during gear shifts,i.e., changes of gear state, between at least adjacent gear states, aclutch engaged or activated in both gear states will remain engaged oractivated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members; three interconnecting members continuouslyinterconnecting a member of the first, second, third and fourthplanetary gear sets with another member of the first, second, third andfourth planetary gear sets; and six torque transmitting mechanismswherein four of the six torque transmitting mechanisms are eachselectively engageable to interconnect at least one of the first, secondand third members with at least one other of the first, second, thirdmembers and wherein two of the six torque transmitting mechanisms areeach selectively engageable to interconnect at least one of the first,second and third members with the stationary member, and wherein the sixtorque transmitting mechanisms are selectively engageable incombinations of at least three to establish a plurality of forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 2. The transmission of claim 1 wherein the threeinterconnecting members further comprises a first interconnecting membercontinuously interconnecting the second member of the first planetarygear set with the second member of the third planetary gear set and thefirst member of the fourth planetary gear set, a second interconnectingmember continuously interconnecting the third member of the firstplanetary gear set with the first member of the second planetary gearset and a third interconnecting member continuously interconnecting thethird member of the second planetary gear set with the third member ofthe third planetary gear set.
 3. The transmission of claim 2 wherein afirst of the six torque transmitting mechanisms is selectivelyengageable to interconnect the second member of the second planetarygear set and the input member with the third member of the fourthplanetary gear set.
 4. The transmission of claim 3 wherein a second ofthe six torque transmitting mechanisms is selectively engageable tointerconnect the third member of the third planetary gear set with thethird member of the fourth planetary gear set.
 5. The transmission ofclaim 4 wherein a third of the six torque transmitting mechanisms isselectively engageable to interconnect the first member of the thirdplanetary gear set with the third member of the fourth planetary gearset.
 6. The transmission of claim 5 wherein a fourth of the six torquetransmitting mechanisms is selectively engageable to interconnect thefirst member of the third planetary gear set with the second member ofthe fourth planetary gear set.
 7. The transmission of claim 6 wherein afifth of the six torque transmitting mechanisms is selectivelyengageable to interconnect the first member of the first planetary gearset with the stationary member.
 8. The transmission of claim 7 wherein asixth of the six torque transmitting mechanisms is selectivelyengageable to interconnect the third member of the first planetary gearset with the stationary member.
 9. The transmission of claim 1 whereinthe input member is continuously connected for common rotation with thesecond member of the second planetary gear set.
 10. The transmission ofclaim 1 wherein the output member is continuously connected for commonrotation with the second member of the fourth planetary gear set. 11.The transmission of claim 1 wherein the third member of the firstplanetary gear set, the first member of the second planetary gear set,the third member of the third planetary gear set and the third member ofthe fourth planetary gear set are sun gears, the second members of thefirst, second, third and fourth planetary gear sets are carrier membersand the first member of the first planetary gear set, the third memberof the second planetary gear set, the first member of the thirdplanetary gear set and the first member of the fourth planetary gear setare ring gears.
 12. A transmission comprising: an input member; anoutput member; first, second, third and fourth planetary gear sets eachhaving first, second and third members; a first interconnecting membercontinuously interconnecting the second member of the first planetarygear set with the second member of the third planetary gear set and thefirst member of the fourth planetary gear set; a second interconnectingmember continuously interconnecting the third member of the firstplanetary gear set with the first member of the second planetary gearset; a third interconnecting member continuously interconnecting thethird member of the second planetary gear set with the third member ofthe third planetary gear set; and six torque transmitting mechanismseach selectively engageable to interconnect at least one of the first,second, and third members with at least one other of the first, second,third members and the stationary member, and wherein the six torquetransmitting mechanisms are selectively engageable in combinations of atleast three to establish a plurality of forward speed ratios and atleast one reverse speed ratio between the input member and the outputmember.
 13. The transmission of claim 12 wherein a first of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe second member of the second planetary gear set and the input memberwith the third member of the fourth planetary gear set.
 14. Thetransmission of claim 13 wherein a second of the six torque transmittingmechanisms is selectively engageable to interconnect the third member ofthe third planetary gear set with the third member of the fourthplanetary gear set.
 15. The transmission of claim 14 wherein a third ofthe six torque transmitting mechanisms is selectively engageable tointerconnect the first member of the third planetary gear set with thethird member of the fourth planetary gear set.
 16. The transmission ofclaim 15 a fourth of the six torque transmitting mechanisms isselectively engageable to interconnect the first member of the thirdplanetary gear set with the second member of the fourth planetary gearset.
 17. The transmission of claim 16 wherein a fifth of the six torquetransmitting mechanisms is selectively engageable to interconnect thefirst member of the first planetary gear set with the stationary member.18. The transmission of claim 17 wherein a sixth of the six torquetransmitting mechanisms is selectively engageable to interconnect thethird member of the first planetary gear set with the stationary member.19. The transmission of claim 12 wherein the input member iscontinuously connected for common rotation with the second member of thefirst planetary gear set.
 20. The transmission of claim 12 wherein theoutput member is continuously connected for common rotation with thesecond member of the fourth planetary gear set.
 21. The transmission ofclaim 12 wherein the third member of the first planetary gear set, thefirst member of the second planetary gear set, the third member of thethird planetary gear set and the third member of the fourth planetarygear set are sun gears, the second members of the first, second, thirdand fourth planetary gear sets are carrier members and the first memberof the first planetary gear set, the third member of the secondplanetary gear set, the first member of the third planetary gear set andthe first member of the fourth planetary gear set are ring gears.
 22. Atransmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having a sun gear, acarrier member and a ring gear, wherein the input member is continuouslyconnected for common rotation with the carrier member of the secondplanetary gear set, and wherein the output member is continuouslyconnected for common rotation with the carrier member of the fourthplanetary gear set; a first interconnecting member continuouslyinterconnecting the carrier member of the first planetary gear set withthe carrier member of the third planetary gear set and the ring gear ofthe fourth planetary gear set; a second interconnecting membercontinuously interconnecting the sun gear of the first planetary gearset with the sun gear of the second planetary gear set; a thirdinterconnecting member continuously interconnecting the ring gear of thesecond planetary gear set with the sun gear of the third planetary gearset; a first torque transmitting mechanism selectively engageable tointerconnect the carrier member of the second planetary gear set and theinput member with the sun gear of the fourth planetary gear set; asecond torque transmitting mechanism selectively engageable tointerconnect the sun gear of the third planetary gear set with the sungear of the fourth planetary gear set; a third torque transmittingmechanism selectively engageable to interconnect the ring gear of thethird planetary gear set with the sun gear of the fourth planetary gearset; a fourth torque transmitting mechanism selectively engageable tointerconnect the ring gear of the third planetary gear set with thecarrier member of the fourth planetary gear set; a fifth torquetransmitting mechanism selectively engageable to interconnect the ringgear of the first planetary gear set with the stationary member; and asixth torque transmitting mechanism selectively engageable tointerconnect the sun gear of the first planetary gear set with thestationary member, and wherein the torque transmitting mechanisms areselectively engageable in combinations of at least three to establish aplurality of forward speed ratios and at least one reverse speed ratiobetween the input member and the output member.